Efficient Watermark Detection - A system and a method of effectively detecting watermarks in a significant amount of data signals. The method, in overview, consists in pre-filtering the significant amount of data signals in order to eliminate from the final watermark detection the segments of the data signals which have no significant relevance to the owner of the copyrights of the watermark under investigation, and then performing the actual watermark detection over the remaining segments of data signals relevant to the investigation. The pre-filtering feature being implemented by a definition of one or more goal descriptors, extraction of one or more descriptors from the data signals and its content and a comparison between goal descriptors and extracted descriptors.

Remote Informed Watermark Detection System - A system and a method for secure remote informed watermark detection making use of a side-information. The system in overview comprises a remote detector and a server computing system wherein a database with side-information assigned to specific descriptors of data signals is stored at the server computing system and wherein a remote detector intending to identify the watermark of a data signal will derive the descriptor of the data signal and subsequently contact the trusted server computing system in order to obtain the necessary side-information for the informed watermark detection.

Encoding With Watermarking Prior to Phase Modulation - In watermarking systems, hackers may try to remove the watermark using a so-called collusion attack. If the attacker has access to multiple identical signals with different watermarks (this typically occurs in electronic content delivery systems), simply averaging the signals will remove the watermark energy. A known solution to this problem is phase modulation. By modulating the phase of the signals, the averaging attack will cause phase cancellation to occur and annoying artifacts to be introduced. In the prior art, said phase modulation is carried out in the base-band domain, prior to watermark embedding. The present invention enables phase modification efficiently to be applied to transform coded signals, in particular DCT or MDCT coded signals such as MP3 or AAC audio signals, or MPEG2 video signals. The bitstream is partially decoded (

11-06-2008

20080301456

Efficient Secure Forensic Watermarking - The invention relates to a watermark generation method for generating watermarks to be embedded in digital media, where said watermark is generated by combining at least two watermark patterns from a set of watermark patterns. The set of watermark patterns are divided into at least two subsets of watermark patterns, and the subsets are hierarchically related and the watermark patterns in said watermark are directly related watermark patterns. Directly related means that the watermark patterns are related like parent and child in a hierarchical structure e.g. a tree structure. Further, the invention relates to an apparatus adapted to generate watermarks to be embedded in media.

12-04-2008

20080310629

Multibit Forensic Watermark with Encrypted Detection Key - The invention relates to embedding auxiliary data in the form of a multibit payload in a host signal, and encrypting the associated detection key. Moreover, the invention relates to extracting the auxiliary data in the form of the multibit payload from a data signal. Auxiliary data is embedded in a host signal by the following steps. First a reference watermark is provided, subsequently an encrypted detection key associated only with the reference watermark is generated. The encrypted detection key may be a scrambled version of the watermark. In a further step, the multibit watermark is generated and a multibit payload is encoded into the reference watermark. Finally, the multibit watermark is embedded into the host signal.

12-18-2008

20090013188

Search for a Watermark in a Data Signal - The invention relates to a method of searching for a watermark in a data signal, and to a watermark detector, such as a copy-control watermark detector. The search is conducted in order to find a watermark in content which possibly has been attacked and/or altered. The search is conducted by the steps of determining or setting a search space for the data signal, selecting a subspace of the search space, and searching for the presence of the watermark in the subspace. The subspace may be selected from a multitude of regions, the selection e.g. being based on a deterministic or probabilistic function.

WARERMARKING AND ENCRYPTION OF ENTROPY-CODED DATA USING ADDITIVE HUFFMAN TABLE - A secure forensic watermarking system is disclosed that distributes the same encrypted content to all users. The decryption key is different for each user, so that the decrypted content differs slightly from the original, i.e. is watermarked. Forensic tracking is possible by distributing unique decryption keys to individual users. The invention allows a forensic mark to be securely embedded in the compressed domain signal. In an embodiment of this invention, the content (x) and an encryption sequence (r) are entropy encoded using a homomorphic Huffman table. A homomorphic Huffmann table is a table H having the property that there exists an operation f( ) such that H-

07-15-2010

20100306550

DEFINING CLASSIFICATION THRESHOLDS IN TEMPLATE PROTECTION SYSTEMS - A method for configuring a biometric template protected authentif ication system, in which the desired classification threshold (T) is first selected to optimize the trade-i off between FAR and FRR of the system, and then the ECC used in the authentif ication process is chosen such that the number (b) of errors which can be corrected thereby is equal to or greater than the selected classification threshold. During authentif ication, the number (b) of errors in a first codeword derived from biometric data associated with a physical object is determined and used in the decision process to accept or reject authentif ication.